Hydrogen energy has been attracting attention in recent years from the viewpoint of minimizing the air pollution and the global warming that arise due to consumption of fossil fuel and reducing the risk of radiation exposure due to utilization of atomic energy. Since hydrogen can be generated by electrolysis of water, it can safely be said that hydrogen exists almost inexhaustibly on earth. Also, it is a clean energy source that does not give off any carbon dioxide when combusted. This is a main reason why hydrogen attracts attention.
Meanwhile, hydrogen needs to be stored safely and efficiently for the utilization of hydrogen. Known currently commercially available hydrogen storing methods include a method of putting hydrogen into a high pressure tank and hermetically sealing the tank, a method of storing hydrogen in the inside of hydrogen storage alloys and a method of storing hydrogen as liquid hydrogen.
However, the above listed hydrogen storing methods are hardly commercially feasible for utilizing hydrogen as energy source because they involve problems such as that they require a huge amount of money as capital investment and that they provide only a poor hydrogen storing capacity.
On the other hand, benzene and cyclohexane are known as cyclic hydrocarbon compounds having a same number of carbon atoms. While benzene is an unsaturated hydrocarbon compound partially having double bonds for bonding carbon atoms, cyclohexane is a saturated hydrocarbon compound having no double bond for bonding carbon atoms. For this reason, cyclohexane is obtained by adding hydrogen to benzene, whereas benzene is obtained by removing part of the hydrogen atoms of cyclohexane. Similarly, decalin is obtained by hydrogenation of naphthalene, whereas naphthalene is obtained by dehydrogenation of decalin. Organic compounds such as saturated hydrocarbon compounds that can externally supply hydrogen by way of dehydrogenation are referred to as “organic hydrides” hereinafter. Thus, hydrogen can be stored and supplied by utilizing hydrogenation and dehydrogenation of hydrocarbon compounds. Such techniques for storing and supplying hydrogen are expected in the field of providing automobiles with motive power and also in the field of power generation (refer to, e.g., Patent Document 1)
Patent Document 1: JP 2002-187702 A (abstract and so on)